Plant productivity is affected by several factors, one of the major ones being insect damage. Both chewing and sucking pests feed on plant leaves, shoots, roots, fruits, flowers and grains leading to considerable loss of yield. Insect infestation is one of the major concerns for crop production. In this regard, it is necessary to develop novel approaches to reduce crop losses to insects and thereby increase net yield. Genetic transformation is a powerful tool for production of crop plants with increased resistance to phytopathogens. A number of transgenic cultivars with elevated tolerance to economically important pests and disease agents are in commercial production. However, in most of these the transgene is driven by a powerful constitutive promoter, such as the cauliflower mosaic virus 35S (CaMV 35S) promoter and its derivatives, and is expressed at high levels even in the absence of pathogen invasion. Continuous synthesis and high accumulation of transgene products, especially toxins, could interfere with plant metabolic pathways and the overall expression of other valuable traits and reduce yields. The above mentioned strategies, although effective, are associated with several problems that affect yield such as:                Abnormalities in plant growth (leading to yield penalty) due to high level expression of the toxic proteins which even affect normal plant development (Barton et al., 1987; Diehn et al., 1996; Rocher et al., 1998; Sachs et al., 1998; Rawat et al., 2011).        Reduced frequency of transgene incorporation in many plants (due to high levels of toxic protein that affect regeneration) as a result of which a much larger number of calli have to be created to get the requisite number of transformants (Rawat et al., 2011).        Reduced expression of insecticidal protein at times of flowering (especially with the most commonly used CaMV35S promoter, which shows reduced expression at the time of flowering) in plants like cotton and maize leading to susceptibility to insect attack during flowering and boll formation by boll worm which reduces yields (Kranthi et al., 2005).        Diversion of vital plant resources towards maintaining high levels of toxic protein even when they are not needed.        
In contrast, the use of promoters of plant defensive genes has distinct advantages because most of them are activated only when the plant is attacked by pests or pathogens. The use of native plant promoters can also help to avoid transgene silencing often associated with the presence of promoters of non-plant origin in the plant genome and particularly the CaMV35S promoter [Matzke et al., Plant Physiol. 107 (1995) 679-685]. Plants have developed a variety of physical and biochemical defense barriers against pests and pathogens. Mechanical wounding of plant tissue (mimicking pathogen invasion or insect chewing) leads to the accumulation of mRNAs that encode proteins thought to be involved in plant defense [Bowles, Annu. Rev. Biochem. 59 (1990) 873-907], and provides a convenient system to isolate and study defense-related genes and their upstream regulatory regions in transgenic host. Some of the promoters developed include the AoPR1 promoter from Asparagus that is activated in 6 hours (Warner et al., 1993; Gulbitti-Onarici et al., 2009), the Shpx6B promoter from Stylosanthes humili speroxidise gene which is activated in 24-48 hours after insect feeding (Perrera and Jones, 2004). However, the time taken for activation of these promoters (6-48 hours) is rather long considering that insects take a much shorter time to feed on and initiate damage on plants. Thus identification of strong wound inducible promoters that express target proteins rapidly only at the time of wounding and their utilization for expression of insecticidal proteins is desirable.